Normal values for sagittal spinal alignment: a study of Brazilian subjects

OBJECTIVES: The purpose of this study is to investigate the normal values of and chain of correlations between spinopelvic parameters in a Brazilian population. METHODS: This is a prospective observational study including asymptomatic adult subjects who had full spinal radiographs performed. The subjects were stratified by age into 3 groups (18-39 years old, 40-59 years old, and >60 years old), and radiographic parameters were compared across age groups and gender using ANOVA and Student's t-test, respectively. The relationships between various radiographic parameters were evaluated with Pearson correlation coefficients. RESULTS: One hundred and thirty asymptomatic volunteers (mean age, 48 years) met the inclusion criteria. The mean sagittal parameters in a normal Brazilian population were as follows: lumbar lordosis (LL) of 56.8°, pelvic tilt (PT) of 12.4°, pelvic incidence (PI) of 49.4°, PI-LL of -7.4°, T1 pelvic angle (TPA) of 8°, sagittal vertical axis (SVA) of -0.54 cm and T1 slope of 25.2°. Subjects ≥60 years old had significantly higher values of SVA (p=0.024) and TPA (p=0.009) than the two younger age groups. The TPA was significantly correlated with the following spinopelvic parameters: LL (r=-0.172, p=0.005), PT (r=0.776, p<0.001), PI (r=0.508, p<0.001), PI-LL (r=0.717, p<0.001), SVA (r=0.409, p<0.001) and T1 slope (r=0.172, p=0.050). CONCLUSION: This study demonstrated significant physiologic trunk inclination with increasing age. The TPA, an angular parameter of global spinal alignment, presented a chain of correlations with different spinal segments.

Adult spine deformity - an overview of radiographic and clinical considerations / Deformidade da coluna vertebral do adulto - panorama das considerações clínicas e radiográficas / Deformidad de la columna vertebral del adultos - visión general de las consideraciones clínicas y radiográficas

ABSTRACT Adult spine deformity is a complex pathology that represents a public health problem with a deep impact on society. When evaluating the patient, not only the clinical and radiographic aspects are essential, but also the clear understanding of the specific needs and expectations of the individual. To elaborate the treatment plan it is necessary to quantify the pain and disability, as well as the spinopelvic alignment of the patient, including the mechanisms that may be recruited to compensate for deformity. Considering these factors, it is possible to define objectives for the surgical correction in order to obtain clinical improvement.

RESUMO A deformidade da coluna vertebral do adulto é uma patologia complexa que representa um problema de saúde pública com profundo impacto na sociedade. Ao avaliar o paciente, não só os aspectos clínicos e radiográficos são essenciais, mas também o claro entendimento das necessidades e expectativas do indivíduo. Para elaborar o plano de tratamento, é necessário quantificar a dor e incapacidade do paciente, além do alinhamento espinopélvico, incluindo-se os mecanismos que podem estar sendo recrutados para compensar a deformidade. Considerando esses fatores, é possível definir os objetivos para a correção cirúrgica visando obter melhora clínica.

RESUMEN La deformidad de la columna vertebral de adultos es una enfermedad compleja que representa un problema de salud pública con un profundo impacto en la sociedad. Al evaluar el paciente, no sólo los aspectos clínicos y radiográficos son esenciales, sino también una clara comprensión de las necesidades y expectativas individuales. Para preparar el plan de tratamiento, es necesario cuantificar el dolor y la discapacidad del paciente, además de la alineación espinopélvica, teniendo en cuenta los mecanismos que pueden ser reclutados para compensar la deformidad. Teniendo en cuenta estos factores, se puede establecer objetivos para la corrección quirúrgica con el fin de obtener una mejoría clínica.